<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    
</body>
<script>
    // 警告框
    let name = "李华"
    let age = 45
    alert(`您的姓名：${name} \n 您的年龄：${age}`)

    // 确认框
    let a = confirm('您确定退出么？')
    // 点击确定返回true，点击取消返回false
    console.log(a)

    // 输入框
    let b = prompt("请输入您的卡号：")
    console.log(b)
    console.log(typeof b)  // string
</script>
</html>